a. Field of the Invention
The present invention relates to an optoelectronic device having a hermetically sealed optoelectronic component and to a method of forming the device, for example optical transmitter or receiver device for use in a fibre optic communications network.
b. Related Art
Optoelectronic transmitter or receiver modules, referred to herein individually and in combination as an “optical transceiver module”, are often formed from a number of sub-assemblies that need to be optically aligned with respect to each prior to being secured together during manufacture of the device. For example, an optical transceiver module will normally have a sub-assembly that includes a hybrid circuit on a ceramic substrate, including an optoelectronic component such as a photodetector or a laser diode connected to associated electronic circuitry for receiving or transmitting a signal from/to the optoelectronic component. The component may need to be optically aligned with optical elements such as lenses or an optical isolator in another sub-assembly. During manufacture, these sub-assemblies need to be brought together, optically aligned and then secured together. It is sometimes necessary to seal the optoelectronic components within the transceiver module in order to achieve an adequate lifetime for the component in harsh environmental conditions.
In a production environment it can be difficult to maintain alignment and form a hermitic seal at the same time. Usually a hermetic seal can be formed using a welding process, but this requires expensive equipment, which may have to be adapted for reasons of convenience and operator safety so that this can be used in proximity with optical alignment apparatus. Many welding techniques also induce shifts in alignment of the components being welded owing to induced thermal stresses. Because of this, it may be preferable to join components using an adhesive such as an epoxy glue, even though this will not ultimately provide a good hermitic seal in harsh environmental conditions.
It is an object of the present invention to provide a more convenient hermetically sealed optoelectronic device and a process for forming for forming such a hermetically sealed optoelectronic device.